Gilbert Ryle (1900-76) was a philosopher who taught at Oxford, and who made important contributions to the philosophy of mind and "ordinary language philosophy." His most important writings included Philosophical Arguments (1945), The Concept of Mind (1949), Dilemmas (1954), Plato's Progress (1966), and On Thinking (1979).

The Concept of Mind (1949) is a critique of the notion that the mind is distinct from the body, and is a rejection of the theory that mental states are separable from physical states. According to Ryle, the classical theory of mind, as represented by Cartesian rationalism, asserts that there is a basic distinction between mind and matter. However, the classical theory makes a basic "category-mistake," because it attempts to analyze the relation betwen "mind" and "body" as if they were terms of the same logical category. This confusion of logical categories may be seen in other theories of the relation between mind and matter. For example, the idealist theory of mind makes a basic category-mistake by attempting to reduce physical reality to mental reality, and the materialist theory of mind makes a basic category-mistake by attempting to reduce mental reality to physical reality.

Ryle rejects Descartesí theory of the relation betwen mind and body, on the grounds that it approaches the investigation of mental processes as if they could be isolated from physical processes. In order to demonstrate how this theory is misleading, he explains that knowing how to perform an act skillfully may be not only a matter of being able to reason practically, but also a matter of being able to put practical reasoning into action. Practical actions may not necessarily be produced by highly theoretical reasoning or complex sequences of intellectual operations. The meaning of actions may be explained not by making inferences about hidden mental processes, but by examining the rules that govern those actions.

According to Ryle, mental processes are merely intelligent acts.1 There are no mental processes distinct from intelligent acts. The operations of the mind are not merely represented by intelligent acts; they are those intelligent acts. Thus, acts of learning, remembering, imagining, knowing, or willing are not merely clues to hidden mental processes or complex sequences of intellectual operations; they are the way in which those mental processes or intellectual operations are defined. Logical propositions are not merely clues to modes of reasoning; they are those modes of reasoning.

The rationalist theory that the will is a faculty within the mind, and that volitions are mental processes that the human body transforms into physical acts, is therefore a misconception. This theory mistakenly assumes that mental acts are distinct from physical acts, and that there is a mental world distinct from the physical world. This theory of the separability of mind and body is described by Ryle as "the dogma of the ghost in the machine."2 He explains that there is no hidden entity called "the mind" inside a mechanical apparatus called "the body." The workings of the mind are not an independent mechanism that governs the workings of the body. The workings of the mind are not distinct from the actions of the body; they are rather a way of explaining the actions of the body.

Cartesian theory holds that mental acts determine physical acts, and that volitional acts of the body must be caused by volitional acts of the mind. This theory is "the myth of the ghost in the machine."3

There is no contradiction between saying that a given action is governed by physical laws, and that it is governed by principles of reasoning. The motives of observable actions are not hidden mental processes; they are propensities or dispositions that explain why these behaviors occur. For example, the disposition to want or not want something is not explained by an intellectual act of wanting or not wanting that thing. The disposition to want something is explained by the behaviors that are involved in wanting that thing. Thus, the mind consists of various abilities or dispositions that explain such behaviors as learning, remembering, knowing, feeling, or willing. However, personal abilities or dispositions are not the same as mental processes or events. To refer to abilities or dispositions as if they are mental occurrences is to make a basic kind of category-mistake.

The nature of a personís motives may be defined by the actions and reactions of that person in various circumstances or situations. The nature of a personís motives in a particular situation may not necessarily be determined by any hidden mental processes or intellectual acts within that person. Motives may be revealed or explained by a personís behavior in a situation.

Ryle criticizes the theory that the mind is a place where mental images are apprehended, perceived, or remembered. Sensations, thoughts, and feelings do not belong to a mental world distinct from the physical world. Knowledge, memory, imagination, and other abilities or dispositions do not reside "within" the mind as if the mind were a space in which these dispositions could be situated or located. Furthermore, dispositions are not the same as behavioral actions. Actions may, however, be explained by dispositions.

Dispositions are neither visible nor hidden, because they are not in the same logical category as behavioral actions. Dispositions are not mental processes or intellectual acts; they are propensities that explain various modes of behavior. Perceptions, thoughts, emotions, and feelings may be understood as observable behaviors that have various modes of production.

Ryle admits that his approach to the theory of mind is behavioristic in being opposed to the theory that there are hidden mental processes that are distinct from observable behaviors. His approach is based on the view that actions such as thinking, remembering, feeling, and willing are revealed by modes of behavior or by dispositions to modes of behavior. At the same time, however, he criticizes both Cartesian theory and behaviorist theory for being overly mechanistic. While Cartesian theory may insist that hidden mental events produce the behavioral responses of the conscious individual, behaviorism may insist that stimulus-response mechanisms produce the behavioral responses of the conscious individual. Ryle says that both Cartesian theory and behaviorist theory may be too rigid and mechanistic to provide us with an adequate understanding of the concept of mind.